Turbine.



G. ROTH.

TUBBINE.

APPLIUATION FILED JUNI'. 24, 190s.

- 902,252. Patented oct. 27, 1908.

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CARL ROTH, OF ZEHLENDORF, NEAR BERLIN, GERMANY.

\ TURB INEI Specification of Letters Patent.

Patented Oct. 27, 1908.A

Application led June 24, 1908. Serial No. 440,182.

of the kind in which the first expansion stage takes place in a velocity flow turbine and the later expansion stages take place in pressure iiow turbines. In such turbines when the stages are arranged co-axially the velocity stage is made of larger diameter than the first pressure How stage. It is also usual in turbines to arrange the pressure flow stages on parts of the drum of diHerent diameters.

In such turbines employing pressure flow stages the end balancing by means of a single dummy piston or balancing surface ar ranged at thestep from the velocity flow turbine to the first stage of the pressure flow turbine has not proved to be efficient under all 'onditions-of loading. Thus if the conditions are arranged for full loading with condensation of the exhaust steam then should the load be diminished 0r should the turbine work with ordinary exhaust into the atmosphere, the balancing effect is to a great extent lost. In order to avoid these diiiculties the present invention relates to a construction of balancing means for such mixed turbines, in which a plurality of the dummy pistons or balancing surfaces are employed one for each ofthe diameters of the pressure flow part, the rst dummy piston being the annular surface formed at the step between the velocity How turbine and the first dia m`eterof the pressure flow turbine.

The invention is illustrated in the accompanying drawings in a diagrammatical manner.

Figure l is a section diagrammatically illustrating one arrangement of turbine acA cording to the present invention, Fig. 2 illustrates a modified arrangement.

According to the form shown in Fig. 1 steam enters by the pipe a and passes through the velocity flow turbine t, the partially expanded steam then passes to those stages of the pressure iow turbine which are arranged oli-'the first' diameter c. At the ste from the diameter of the velocityow tur ine b to the turbine stages c there is ar-4 ranged an annular dummy piston surface k.

It will be seen that-the velocity flow stage b is between the labyrinth packing 7L and the dummy piston g. The steam after passing through the pressure flow stages c reaches'- the chamber 7c and then passes through thepressure flow stages al arranged on a part of the drum of larger diameter than the stages c. The stages d communicate with the exhaust n.

In Fig. l at the high pressure end of the turbine there'is arranged a dummy piston formed by the annular surface between thev parts of the diameters marked e and f on the drawing. The chamber Z in front of this dummy pistonI is placed in communication with the chamber ic by means of a pipe m. The center of the drum is placed in communication with the exhaust pipe n, and the.- space l is in a fluid-tight manner separated fromthe interior of the-drum by means of labyrinth packing z'. Y

It will b e seenthat the dummy pistoni g is subjected to the pressure of partially eX- panded steam and this dummy piston is sufficient to counteract the unbalanced end pressures occurring in the stages c. The dummy piston surface between the diameters e and f is arranged to balance the unbalanced end pressures in the stages d. By this arrangement the regulation of the end balancing pressure proceeds in an exceedingly automatio manner, without the employment of a complicated mechanism employing the end movement of the turbine shaft.

According to the form of this invention shown in Fig. Q the packing h is arranged 4as described with reference to the packing h in Fig. l as also is the' dummy piston surface 95l g. The space 7c between the stages c and el is placed in communication With'the center of the drum by means of an opening 0, ther packing z" is arranged at the low pressure end of the turbine. In this form the surface marked D in Fig. 2 forms thesecond balancing surface or 'dummy piston for those stages of the turbine which are arranged on the part of the drum of larger diameter.

The' operation of thisdevice proceedsmin 105 substantially the same automatic manner as described with-reference to Fi 1. The

diameter f in Fig. 1 however is su stantially the average diameter of thepressure flow parts cl. 110

I claim A 1 In a mixed turbine havingla high pressure velocity flow stage and a plurality of pressure flow stages arranged (zo-axially in series therewith on parts of the drum of different diameter, the diameter of the rst pressure flow stage being less than that of the Velocity liow stage, end balancing means for the pressure flow parts comprising separate dummy pistons for each of the diameters of said pressure flow parts, the dummy piston surface for the first pressure iiow stages being the step in the diameter from the velocity flow turbine to the diameter on which said stages are arranged, and a labyrinth packing arranged before the velocity How part.

2. In a mixed turbine having a high pressure velocity flow stage and a plurality of pressure flow stages arranged co-aXially in series therewith on parts of the drum of different diameter, the diameter of the first pressure flow stage being less than that of the velocity iiow stage, end balancing means for the pressure How parts comprising separate dummy pistons for each of the diametersl of said pressure iiow parts7 the dummy piston surface for the rst pressure flow stages being the step in the diameter from the velocity flowturbine to the diameter on which said stages are arranged, and a labyrinth pac-king arranged before the velocity flow parts, said packing being subjected on its low pressure side to the pressureat the step l from the diameter of the first pressure flow stages to the diameter on which the second set of pressure flow stages are arranged.

3. In a mixed turbine having a high pressure velocity flow stage and a plurality of pressure flow stages arranged (Jo-axially in series therewith on parts of the drum of different diameter, the diameter of the first pressure flow stage being less than that of the velocity How stage, end balancing means for the pressure flow parts comprising separate dummy pistons for each of the diameters of said pressure flow parts, the dummy piston surface for the first pressure How stages being the step in the diameter from the velocity flow turbines to the diameter on which said stages are arranged, and a labyrinth packing arranged before the velocity flow part, said packing being subjected on its low pressure side to the pressure at the step from the diameter ofthe first pressure iiow stages to the diameter on which the second set of pressure How stages are arranged, a further packing arranged also at the high pressure end of the turbine and adapted to preserve the pressure diife'rence between the said intermediate pressure and the exhaust.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

CARL RTH. 

